Might be worth phoning him and asking him what spring rates he recommends for what you're asking just to see so you can compare with what others might be using, will be written or a sticker on the springs anyway though when they turn up to be fair!
I was wanting a track setup and had been told by someone who prepares race cars what to ask for, but he did say he thought the rates i asked for were a bit much so we decided i'd have a softer set that he recommended for the rear.
In all fairness he did seem to know what he was on about and springs are pretty cheap tbh so probably worth going with what he suggests and see how you get on, can always order more springs in the future